The invention concerns an apparatus and a method for the mounting of teeth onto saw blade blanks, wherein the apparatus comprises a tooth introduction device, a receiving device for the saw blade blank, and a mounting device for attaching the teeth to the saw blade blank.
This type of apparatus has become known in the art through DE 37 17 610 C2.
The conventional device facilitates the automatic soldering of hard metal teeth onto a circular saw blade. A rotational device is utilized to position each recess on the blank of the circular saw blade to seat on a hard metal tooth. As soon as the hard metal tooth is adjacent to the blank of the circular saw blade, the tooth is soldered to the blank. After all teeth have been soldered to the blank the saw blade is ground on both sides so that the hard metal tooth sides do not protrude in an unacceptable fashion or irregularly beyond the side surfaces of the blank. If the teeth which are to be soldered are incorrectly positioned on the saw blade blank, the teeth are soldered to the blank with unacceptable orientation and post-processing is required such that the manufactured saw blade has the correct dimensions. This increases the amount of grinding material used. In addition, the teeth used must have a sufficient width. In order to align the teeth with respect to the blank of the saw blade the blank is aligned prior to the soldering process and all the teeth are subsequently soldered. In this procedure there is a particular tolerance with which the teeth can be mounted to the blank independent of the quality of the soldering. Current tolerances, i.e. solderings, have a tolerance range of 0.05 through 0.2 mm relative to a predetermined position on the saw blade blank. The sides of the teeth are subsequently ground so that they do not protrude or, preferentially, protrude evenly.
It is the purpose of the present invention to create a method and a device which facilitate the attachment of teeth to saw blades in such a fashion that lower tolerances are achieved than in prior art so that the subsequent post-processing procedure can be eliminated or requires substantially less time.
With regard to the method, the purpose of the invention is solved in that the tooth or the teeth and the saw blade blank are measured and, subsequently, the recorded data are analyzed. An analysis unit then determines the configuration of each individual tooth on the saw blade blank so that each tooth is mounted to the saw blade blank to either be flush with the side surface of the saw blade blank or, taken into consideration the dimensioning of the saw blade blank and each individual tooth, is introduced with a minimum tolerance on the saw blade blank with respect to a predetermined position.
The method in accordance with the invention has the substantial advantage that each tooth can be individually adjusted to a recess on the saw blade blank. The individual tooth can be adjusted and centered on the saw blade blank since all local measurements of the tooth as well as the saw blade blank are recorded by an evaluation unit which controls and coordinates the correlation. The method in accordance with the invention achieves tolerances of xe2x89xa60.04 mm, i.e. in a direction of the tooth relative to a reference plane. Mechanical wear occurring during prolonged operation of an apparatus can be compensated for to a certain extent, since the positioning of each individual tooth relative to the saw blade blank and vice versa is always newly determined. It is also conceivable that the teeth are measured in advance and that the saw blade blank receives only optimally adjusted teeth so that no or only little post-processing is required. The recorded data of a tooth, for example the width, length, thickness, cut angle and the comparable dimensions of the saw blade blank are fed to an evaluation unit which evaluates this data and optimizes correlations. Should additional post-processing steps be necessary after attaching the tooth to the saw blade in the vicinity of the recess, same require substantially less time.
The designation xe2x80x9cminimized tolerancexe2x80x9d relative to a predetermined position on the saw blade blank means that the tooth protrudes as evenly as possible beyond both side surfaces or that the teeth protrude evenly beyond one side surface or that alternate teeth at the left and right protrude beyond the side surfaces in a predetermined pattern. The sides of the teeth could also be flush with one side surface and protrude beyond the other side surface in a defined fashion.
The method in accordance with the invention can be particularly advantageous for the production of circular saw blades having large diameters, since, in this case, large tolerances occur which can be substantially compensated for using this method. In this connection, an increased precision means a more even protrusion of all teeth. The resulting reduction in grinding leads to reduced wear on the grinding wheel. Thin saw blades can be produced having better quality, since radially extending tooth sides can be evenly ground on both sides.
In a preferred embodiment of the method in accordance with the invention, the data recorded by the analysis unit for evaluating each tooth and each saw blade blank are converted into signals which activate the holding means for the tooth and/or the saw blade blank to align, in particular center, each individual tooth in a predetermined fashion and correlate each tool with the saw blade blank. The holding means for the tooth or the saw blade blank can be moved in a controlled fashion and the evaluation unit enables the attachment process, e.g. soldering, only after the individual tooth has been optimally positioned on the saw blade blank or vice versa.
In an additional preferred application of the method in accordance with the invention, the aligned association of a tooth with a saw blade blank, is effected in that either the tooth or the saw blade blank or the tooth and the saw blade blank are moved. This measure minimizes the amount of time needed for the desired positioning of each individual tooth on the saw blade and vice versa.
An additional configuration of the method in accordance with the invention provides that the evaluation unit record the width of each individual tooth and the width of the saw blade blank to, using these characteristic values, determine the configuration of each individual tooth on the saw blade blank. This has the advantage that the recording of only two parameters enables control of the positioning of the tooth relative to the saw blade blank in a safe and precise fashion. The method in accordance with the invention permits the width of saw blades (thickness, strengths) to be determined not only qualitatively but also quantitatively so that the conventional subsequent manual adjustment required when using different saw blade blanks, can be eliminated. The method in accordance with the invention separately reevaluates and determines the width of the saw blade blank and, if required, the width of the saw blade blank in the corresponding tooth region and the machine parameters are automatically adjusted to the changed situation.
In a preferred application of the method in accordance with the invention, the teeth are each initially held at their sides by two movable clamp jaws, in particular ceramic jaws, which record the width of each individual tooth and pass this characteristic value to the evaluation unit. The width of the saw blade blank in the vicinity of the first tooth is then recorded and the sensor provided therefor which determines the width of the saw blade blank, passes these data to the analysis unit. The saw blade blank is shifted, with a stationary tooth, into a position at which the tooth can be joined to the saw blade blank. These means allow the desired relevant geometrical data of the tooth and the saw blade blank to be safely determined so that both an economical and reliable determination of the necessary data is guaranteed during permanent operation.
In connection with the method in accordance with the invention, teeth made from hard metal or diamond are preferentially mounted to circular or band-shaped saw blade blanks. The saw blade blank is made from metal, plastic, or a composition material. In the event that very high quality teeth are mounted to the saw blade base body, the method in accordance with the invention has the advantage that the exact alignment of each individual tooth relative to the saw blade blank minimizes post-processing and, in addition, permits reduced overdimensioning. If post-processing on the hard metal or diamond tooth is not required, the difficult grinding process can be essentially eliminated and expensive high quality material remains on the tooth and is not ground-off.
The teeth are preferentially connected to the saw blade blank via a hard soldering process. This joining technique has proved itself and effects a secure material connection even under strong loading.
With regard to the apparatus, the purpose of the invention is solved in that the tooth introduction device has means for determining the width of each individual tooth and the receiving device for the saw blade blank has means to determine the width of the saw blade blank and the apparatus has an evaluation unit for the data determined by the tooth introduction device and the receiving device for the saw blade blank with evaluation unit driving means for positioning the tooth and/or the saw blade blank to locate each individual tooth on the saw blade blank at predetermined positions using the data from the evaluation unit.
The apparatus in accordance with the invention can be of straight forward construction so that the means determining the measuring values and the means recording the measuring values for the tooth and also for the saw blade blank can be easily monitored. The analysis unit controls the processing.
The mechanical means for holding the materials to be combined as well as the means receiving the measured values and the means communicating the measured values as well as the means for displacing the tooth and/or the saw blade blank can be configured in such a fashion that e.g. the hard soldering step can be carried out with great precision in a very short amount of time.
In an additional preferred configuration of the apparatus, the tooth introduction unit has clamping jaws for the tooth by means of which the analysis unit records and evaluates the position of at least one clamp jaw. A sensor is provided for in the receiving device for the saw blade blank which provides data to the analysis unit suitable for determining the width of the saw blade blank in the vicinity of each individual tooth. The receiving device of the saw blade blank has at least one caliper controlled by the analysis unit which displaces the saw blade blank to an exact predetermined position relative to the tooth. These means allow advantageous use of the method in accordance with the invention.
It is also advantageous when the calipers move the saw blade blank, in the event of a circular saw blade blank, along the rotation axis and, in the event of a band-shaped saw blade blank, transverse to an axial extension of the band. This measure allows for each tooth to be fixed in space and the saw blade blank is displaced into a position which guarantees that e.g. the tooth is centered, i.e. protrudes to an equal extent beyond both sides of the saw blade blank or is flush with the side surfaces of the saw blade blank.
The caliper or calipers can be both means for determining the width of the saw blade blank as well as means for displacing the saw blade blank. This type of configuration of the calipers gives the calipers a double function. The configuration of the components in the vicinity of the hard soldering location is simplified.
Clearly in accordance with the invention only one parameter, either on the tooth and/or on the saw blade blank need be measured and evaluated to achieve the required tolerance improvements of the tooth relative to the saw blade blank. The teeth used can also be pre-ground and subsequently attached to the saw blade blank. In addition, use of the method in accordance with the invention and the apparatus in accordance with the invention provides for a substantial improvement in the precision with which the tooth protrudes beyond the saw blade blank.
Further advantages result from the description of the accompanying drawing. The above mentioned features and those to be further described below can be utilized in accordance with the invention individually or collectively in arbitrary combination. The invention is described more closely below with reference to FIGS. 1, 2 and 3.